The present invention relates to a network relaying apparatus and a network relaying method, or in particular to a network relaying apparatus including a router of a computer network system which is capable of searching at high speed for a destination of a packet input and a network relaying search method.
Generally, in a network system, a network relaying apparatus such as a router or a bridge is used for connecting a plurality of networks. The router checks the destination address of a packet received from a network or a subnet connected, determines the destination of the packet, and transfers the packet to a network or a subnet which is connected with the destination router or host.
FIG. 13 is a diagram showing a configuration of a conventional network relaying apparatus. In FIG. 13, a router 100 includes a routing manager (RM) 110, router buses 120, network interfaces (NIF) 130 and ports 140. Each port 140 is connected to an appropriate network 150.
Each network interface 130 receives a packet from a network connected to the port 140, and transmits the received packet through the router bus 120 to the routing manager 110. The routing manager 110 includes a routing table for holding the routing information, and using this routing information, determines the network 150 of the destination from the address of the packet received, and transmits the packet to the network interface 130 of the port 140 connected to the network 150. The network interface 130 that has received the packet from the routing manager 110 sends out the packet to the destination network 150. The routing manager 110 updates and maintains the routing information held in the routing table based on the header information of the packet received, and has the function of overall management of the router 100.
An explanation will be given of the route search process for searching for a port outputting the next address to which the packet is to be transferred upon receipt of the packet and outputting the packet. Normally, the route search uses a route search table (routing table) prepared from the component definition information and the information obtained by exchange between the routers. The routing table is for searching the information (next hop information) as to the output port, the next hop address and whether the network is directly connected or not with a set of the network address and the network mask length as a key.
As another conventional system, JP-A-05-199230 (U.S. Pat. No. 5,434,863) discloses an internetwork system and a communication network system which can flexibly meet the size requirement of the network without adversely affecting the high-speed routing process. In these systems, a router manager and a plurality of routing accelerator modules are coupled to each other with a high-speed bus Also, each routing accelerator is connected with a plurality of independent communication ports. In these conventional systems, a plurality of the routing accelerators makes possible a high-speed routing and by adding the routing accelerators, the requirement for increasing the network size can be easily met.